The invention concerns a method for the stabilization of folded filter media as well as a filter medium produced by this method. Filter elements of this kind are used as filter elements mostly in connection with terminal disks arranged at the end faces. The zigzag-folded filter media can be supported inwardly on a hollow body, for example, a center tube, for stabilization. As a result of folding, the fold tips on the exterior that are facing away from the center are very unstable. This can lead to denting or buckling of the filter medium when handling this filter element for service purposes or in an operational state.
A method for stabilizing the folds of the filter elements is disclosed in DE 102 44 925 in which a thread impregnated with a hot melt adhesive is wound about the filter medium. For impregnating the thread with hot melt adhesive, the thread is pulled through a molten pool and by means of downstream thread guides is wound onto the filter medium. The thread, when in its plastic state, contacts the filter medium and adheres thus to the external fold tips. However, it has been found that the adhesion between fold thread and the fold tips is often not satisfactory and that the thread, in particular after exposure to moisture, will become detached when subjected to minimal loads.